mirrors/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-12-27 15:51:30 -05:00
Code Issues Packages Projects Releases Wiki Activity

Bluetooth: hci_h5: avoid sending two SYNC messages

Browse Source 
Previously, h5_open() called h5_link_control() to send a SYNC message.
But h5_link_control() only enqueues the packet and requires the caller
to call hci_uart_tx_wakeup(). Thus, after H5_SYNC_TIMEOUT ran out
(100ms), h5_timed_event() would be called and, realizing that the state
was still H5_UNINITIALIZED, it would re-enqueue the SYNC and call
hci_uart_tx_wakeup(). Consequently, two SYNC packets would be sent and
initialization would unnecessarily wait for 100ms.

The naive solution of calling hci_uart_tx_wakeup() in h5_open() does not
work because it will only schedule tx work if the HCI_PROTO_READY bit is
set and hci_serdev only sets it after h5_open() returns. This patch
removes the extraneous SYNC being enqueued and makes h5_timed_event()
wake up on the next jiffy.

Signed-off-by: Javier Nieto <jgnieto@cs.stanford.edu>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Javier Nieto
2025-09-29 15:14:41 -07:00
committed by Luiz Augusto von Dentz
parent 484f117689
commit 01622e9a53
1 changed files with 5 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/bluetooth/hci_h5.c
View File

@@ -213,7 +213,6 @@ static void h5_peer_reset(struct hci_uart *hu)
static int h5_open(struct hci_uart *hu)
{
struct h5 *h5;
const unsigned char sync[] = { 0x01, 0x7e };
BT_DBG("hu %p", hu);
@@ -243,9 +242,11 @@ static int h5_open(struct hci_uart *hu)
set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
/* Send initial sync request */
h5_link_control(hu, sync, sizeof(sync));
mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
/*
* Wait one jiffy because the UART layer won't set HCI_UART_PROTO_READY,
* which allows us to send link packets, until this function returns.
*/
mod_timer(&h5->timer, jiffies + 1);
return 0;
}